269 lines
12 KiB
Python
269 lines
12 KiB
Python
# Support for reading acceleration data from an mpu9250 chip
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#
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# Copyright (C) 2022 Harry Beyel <harry3b9@gmail.com>
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# Copyright (C) 2020-2021 Kevin O'Connor <kevin@koconnor.net>
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#
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# This file may be distributed under the terms of the GNU GPLv3 license.
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import logging, time, collections, threading, multiprocessing, os
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from . import bus, motion_report, adxl345
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MPU9250_ADDR = 0x68
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MPU9250_DEV_ID = 0x73
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MPU6050_DEV_ID = 0x68
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# MPU9250 registers
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REG_DEVID = 0x75
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REG_FIFO_EN = 0x23
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REG_SMPLRT_DIV = 0x19
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REG_CONFIG = 0x1A
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REG_ACCEL_CONFIG = 0x1C
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REG_ACCEL_CONFIG2 = 0x1D
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REG_USER_CTRL = 0x6A
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REG_PWR_MGMT_1 = 0x6B
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REG_PWR_MGMT_2 = 0x6C
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SAMPLE_RATE_DIVS = { 4000:0x00 }
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SET_CONFIG = 0x01 # FIFO mode 'stream' style
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SET_ACCEL_CONFIG = 0x10 # 8g full scale
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SET_ACCEL_CONFIG2 = 0x08 # 1046Hz BW, 0.503ms delay 4kHz sample rate
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SET_PWR_MGMT_1_WAKE = 0x00
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SET_PWR_MGMT_1_SLEEP= 0x40
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SET_PWR_MGMT_2_ACCEL_ON = 0x07
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SET_PWR_MGMT_2_OFF = 0x3F
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FREEFALL_ACCEL = 9.80665 * 1000.
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# SCALE = 1/4096 g/LSB @8g scale * Earth gravity in mm/s**2
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SCALE = 0.000244140625 * FREEFALL_ACCEL
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FIFO_SIZE = 512
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Accel_Measurement = collections.namedtuple(
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'Accel_Measurement', ('time', 'accel_x', 'accel_y', 'accel_z'))
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MIN_MSG_TIME = 0.100
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BYTES_PER_SAMPLE = 6
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SAMPLES_PER_BLOCK = 8
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# Printer class that controls MPU9250 chip
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class MPU9250:
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def __init__(self, config):
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self.printer = config.get_printer()
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adxl345.AccelCommandHelper(config, self)
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self.query_rate = 0
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am = {'x': (0, SCALE), 'y': (1, SCALE), 'z': (2, SCALE),
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'-x': (0, -SCALE), '-y': (1, -SCALE), '-z': (2, -SCALE)}
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axes_map = config.getlist('axes_map', ('x','y','z'), count=3)
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if any([a not in am for a in axes_map]):
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raise config.error("Invalid mpu9250 axes_map parameter")
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self.axes_map = [am[a.strip()] for a in axes_map]
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self.data_rate = config.getint('rate', 4000)
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if self.data_rate not in SAMPLE_RATE_DIVS:
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raise config.error("Invalid rate parameter: %d" % (self.data_rate,))
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# Measurement storage (accessed from background thread)
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self.lock = threading.Lock()
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self.raw_samples = []
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# Setup mcu sensor_mpu9250 bulk query code
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self.i2c = bus.MCU_I2C_from_config(config,
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default_addr=MPU9250_ADDR,
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default_speed=400000)
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self.mcu = mcu = self.i2c.get_mcu()
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self.oid = oid = mcu.create_oid()
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self.query_mpu9250_cmd = self.query_mpu9250_end_cmd = None
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self.query_mpu9250_status_cmd = None
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mcu.register_config_callback(self._build_config)
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mcu.register_response(self._handle_mpu9250_data, "mpu9250_data", oid)
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# Clock tracking
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self.last_sequence = self.max_query_duration = 0
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self.last_limit_count = self.last_error_count = 0
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self.clock_sync = adxl345.ClockSyncRegression(self.mcu, 640)
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# API server endpoints
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self.api_dump = motion_report.APIDumpHelper(
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self.printer, self._api_update, self._api_startstop, 0.100)
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self.name = config.get_name().split()[-1]
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wh = self.printer.lookup_object('webhooks')
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wh.register_mux_endpoint("mpu9250/dump_mpu9250", "sensor", self.name,
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self._handle_dump_mpu9250)
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def _build_config(self):
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cmdqueue = self.i2c.get_command_queue()
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self.mcu.add_config_cmd("config_mpu9250 oid=%d i2c_oid=%d"
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% (self.oid, self.i2c.get_oid()))
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self.mcu.add_config_cmd("query_mpu9250 oid=%d clock=0 rest_ticks=0"
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% (self.oid,), on_restart=True)
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self.query_mpu9250_cmd = self.mcu.lookup_command(
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"query_mpu9250 oid=%c clock=%u rest_ticks=%u", cq=cmdqueue)
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self.query_mpu9250_end_cmd = self.mcu.lookup_query_command(
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"query_mpu9250 oid=%c clock=%u rest_ticks=%u",
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"mpu9250_status oid=%c clock=%u query_ticks=%u next_sequence=%hu"
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" buffered=%c fifo=%u limit_count=%hu", oid=self.oid, cq=cmdqueue)
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self.query_mpu9250_status_cmd = self.mcu.lookup_query_command(
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"query_mpu9250_status oid=%c",
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"mpu9250_status oid=%c clock=%u query_ticks=%u next_sequence=%hu"
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" buffered=%c fifo=%u limit_count=%hu", oid=self.oid, cq=cmdqueue)
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def read_reg(self, reg):
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params = self.i2c.i2c_read([reg], 1)
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return bytearray(params['response'])[0]
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def set_reg(self, reg, val, minclock=0):
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self.i2c.i2c_write([reg, val & 0xFF], minclock=minclock)
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# Measurement collection
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def is_measuring(self):
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return self.query_rate > 0
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def _handle_mpu9250_data(self, params):
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with self.lock:
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self.raw_samples.append(params)
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def _extract_samples(self, raw_samples):
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# Load variables to optimize inner loop below
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(x_pos, x_scale), (y_pos, y_scale), (z_pos, z_scale) = self.axes_map
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last_sequence = self.last_sequence
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time_base, chip_base, inv_freq = self.clock_sync.get_time_translation()
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# Process every message in raw_samples
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count = seq = 0
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samples = [None] * (len(raw_samples) * SAMPLES_PER_BLOCK)
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for params in raw_samples:
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seq_diff = (last_sequence - params['sequence']) & 0xffff
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seq_diff -= (seq_diff & 0x8000) << 1
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seq = last_sequence - seq_diff
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d = bytearray(params['data'])
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msg_cdiff = seq * SAMPLES_PER_BLOCK - chip_base
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for i in range(len(d) // BYTES_PER_SAMPLE):
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d_xyz = d[i*BYTES_PER_SAMPLE:(i+1)*BYTES_PER_SAMPLE]
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xhigh, xlow, yhigh, ylow, zhigh, zlow = d_xyz
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# Merge and perform twos-complement
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rx = ((xhigh << 8) | xlow) - ((xhigh & 0x80) << 9)
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ry = ((yhigh << 8) | ylow) - ((yhigh & 0x80) << 9)
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rz = ((zhigh << 8) | zlow) - ((zhigh & 0x80) << 9)
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raw_xyz = (rx, ry, rz)
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x = round(raw_xyz[x_pos] * x_scale, 6)
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y = round(raw_xyz[y_pos] * y_scale, 6)
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z = round(raw_xyz[z_pos] * z_scale, 6)
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ptime = round(time_base + (msg_cdiff + i) * inv_freq, 6)
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samples[count] = (ptime, x, y, z)
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count += 1
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self.clock_sync.set_last_chip_clock(seq * SAMPLES_PER_BLOCK + i)
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del samples[count:]
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return samples
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def _update_clock(self, minclock=0):
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# Query current state
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for retry in range(5):
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params = self.query_mpu9250_status_cmd.send([self.oid],
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minclock=minclock)
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fifo = params['fifo'] & 0x1fff
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if fifo <= FIFO_SIZE:
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break
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else:
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raise self.printer.command_error("Unable to query mpu9250 fifo")
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mcu_clock = self.mcu.clock32_to_clock64(params['clock'])
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sequence = (self.last_sequence & ~0xffff) | params['next_sequence']
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if sequence < self.last_sequence:
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sequence += 0x10000
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self.last_sequence = sequence
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buffered = params['buffered']
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limit_count = (self.last_limit_count & ~0xffff) | params['limit_count']
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if limit_count < self.last_limit_count:
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limit_count += 0x10000
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self.last_limit_count = limit_count
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duration = params['query_ticks']
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if duration > self.max_query_duration:
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# Skip measurement as a high query time could skew clock tracking
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self.max_query_duration = max(2 * self.max_query_duration,
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self.mcu.seconds_to_clock(.000005))
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return
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self.max_query_duration = 2 * duration
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msg_count = (sequence * SAMPLES_PER_BLOCK
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+ buffered // BYTES_PER_SAMPLE + fifo)
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# The "chip clock" is the message counter plus .5 for average
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# inaccuracy of query responses and plus .5 for assumed offset
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# of mpu9250 hw processing time.
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chip_clock = msg_count + 1
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self.clock_sync.update(mcu_clock + duration // 2, chip_clock)
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def _start_measurements(self):
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if self.is_measuring():
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return
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# In case of miswiring, testing MPU9250 device ID prevents treating
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# noise or wrong signal as a correctly initialized device
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dev_id = self.read_reg(REG_DEVID)
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if dev_id != MPU9250_DEV_ID and dev_id != MPU6050_DEV_ID:
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raise self.printer.command_error(
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"Invalid mpu9250/mpu6050 id (got %x).\n"
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"This is generally indicative of connection problems\n"
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"(e.g. faulty wiring) or a faulty chip."
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% (dev_id))
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# Setup chip in requested query rate
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self.set_reg(REG_PWR_MGMT_1, SET_PWR_MGMT_1_WAKE)
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self.set_reg(REG_PWR_MGMT_2, SET_PWR_MGMT_2_ACCEL_ON)
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time.sleep(20. / 1000) # wait for accelerometer chip wake up
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self.set_reg(REG_SMPLRT_DIV, SAMPLE_RATE_DIVS[self.data_rate])
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self.set_reg(REG_CONFIG, SET_CONFIG)
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self.set_reg(REG_ACCEL_CONFIG, SET_ACCEL_CONFIG)
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self.set_reg(REG_ACCEL_CONFIG2, SET_ACCEL_CONFIG2)
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# Setup samples
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with self.lock:
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self.raw_samples = []
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# Start bulk reading
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systime = self.printer.get_reactor().monotonic()
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print_time = self.mcu.estimated_print_time(systime) + MIN_MSG_TIME
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reqclock = self.mcu.print_time_to_clock(print_time)
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rest_ticks = self.mcu.seconds_to_clock(1. / self.data_rate)
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self.query_rate = self.data_rate
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self.query_mpu9250_cmd.send([self.oid, reqclock, rest_ticks],
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reqclock=reqclock)
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logging.info("MPU9250 starting '%s' measurements", self.name)
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# Initialize clock tracking
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self.last_sequence = 0
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self.last_limit_count = self.last_error_count = 0
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self.clock_sync.reset(reqclock, 0)
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self.max_query_duration = 1 << 31
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self._update_clock(minclock=reqclock)
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self.max_query_duration = 1 << 31
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def _finish_measurements(self):
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if not self.is_measuring():
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return
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# Halt bulk reading
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params = self.query_mpu9250_end_cmd.send([self.oid, 0, 0])
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self.query_rate = 0
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with self.lock:
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self.raw_samples = []
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logging.info("MPU9250 finished '%s' measurements", self.name)
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self.set_reg(REG_PWR_MGMT_1, SET_PWR_MGMT_1_SLEEP)
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self.set_reg(REG_PWR_MGMT_2, SET_PWR_MGMT_2_OFF)
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# API interface
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def _api_update(self, eventtime):
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self._update_clock()
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with self.lock:
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raw_samples = self.raw_samples
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self.raw_samples = []
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if not raw_samples:
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return {}
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samples = self._extract_samples(raw_samples)
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if not samples:
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return {}
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return {'data': samples, 'errors': self.last_error_count,
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'overflows': self.last_limit_count}
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def _api_startstop(self, is_start):
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if is_start:
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self._start_measurements()
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else:
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self._finish_measurements()
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def _handle_dump_mpu9250(self, web_request):
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self.api_dump.add_client(web_request)
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hdr = ('time', 'x_acceleration', 'y_acceleration', 'z_acceleration')
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web_request.send({'header': hdr})
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def start_internal_client(self):
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cconn = self.api_dump.add_internal_client()
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return adxl345.AccelQueryHelper(self.printer, cconn)
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def load_config(config):
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return MPU9250(config)
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def load_config_prefix(config):
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return MPU9250(config)
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